Is. Chang et Mh. Hon, INFLUENCE OF DEPOSITION PARAMETERS ON THE TEXTURE OF CHEMICAL-VAPOR-DEPOSITED TUNGSTEN FILMS BY A WF6 H-2/AR GAS-SOURCE/, Journal of the Electrochemical Society, 145(9), 1998, pp. 3235-3240
Citations number
12
Categorie Soggetti
Electrochemistry,"Materials Science, Coatings & Films
In order to investigate the relationship between the film texture and
the deposition parameters including gas composition, temperatures, and
substrate materials, polycrystalline tungsten films were prepared by
reduction of tungsten hexafluoride with hydrogen. The experimental res
ults show that the orientations of the textured films correlate closel
y with WF6 concentrations in the gas mixture and deposition temperatur
es. High WF6 concentrations enhance the formation of the <100> texture
d films, while low WF6 concentrations facilitate the formation of the
<111> textured films. The <111> texture, usually observed in tungsten
films deposited at high temperatures (greater than or equal to 400 deg
rees C) and high ratios of H-2 to WF6, can also form at low deposition
temperatures (370 degrees C) when the WF6 concentration used is low e
nough (0.6 vol %). The WF6 concentration for obtaining a <100> texture
d film increases with increasing deposition temperatures. On the other
hand. the concentrations of hydrogen gas have minimal influence on th
e formation of the film textures. Therefore, in terms of gas compositi
on, the WF6 concentration, riot the ratio of H-2 to WF6 is a compact f
actor which directly dominates the texture of the films. The effect of
substrate on the film texture was only found in the initial growth st
age. The crystals formed at the beginning of the film growth were rand
omly oriented. A. preferential orientation became pronounced with incr
easing film thickness through the competitive crystal growth.